"Killing marestail in the fall is usually easier since the seedlings and rosettes are small and more susceptible to herbicides. Once weeds like marestail get through the winter, their rosettes start to bolt upwards in the spring, making them much more difficult to control," says Dwight Lingenfelter. 

The decision on when to terminate cover crops may affect the overall yield of the upcoming cash crop. Research is showing that a later termination may result in a lower overall yield. However, that doesn’t mean early termination is right for your field.

Legumes still can provide valuable N to today’s cropping systems. Legumes also contribute a non-nitrogen rotation effect due to addition of soil organic matter and improvement in soil health. Corn grown following alfalfa stands that are 2+ years old (and contained at least 50% alfalfa) require no nitrogen fertilizer on many soils. Red clover N credits are less than for alfalfa.

Several months ago experts from Purdue University discussed the herbicide shortage for the 2022 growing season and outlined a couple of scenarios where growers can switch to alternative herbicides to accomplish the same weed control objectives. In this article, they discuss some options for fields that have a mixture of cover crop species growing in them and how to effectively terminate the cover crops before corn or soybean production.